The present invention relates to a lower vehicle-body structure of an automotive vehicle which comprises a seat-attaching bracket supporting a seat where a passenger is seated.
In a vehicle, such as an automotive vehicle, when another vehicle collides with a vehicle side of an own vehicle or the vehicle side of the own vehicle collides with an obstacle, a side-collision load which is applied from the vehicle side is transmitted and dispersed, by way of one of side sills, a cross member, and a floor panel, to the other side sill. Herein, it is known that the rigidity of a lower vehicle body against this side-collision load for the vehicle which comprises a floor tunnel protruding upward is lower than that for a vehicle which does not comprise the floor tunnel.
Accordingly, the vehicle comprising the floor tunnel is generally configured such that a tunnel reinforcement as a reinforcing member to improve the rigidity of the floor tunnel is provided at a lower-face side of the floor tunnel such that it matches a shape of the floor tunnel.
Japanese Patent Laid-Open Publication No. 2016-210335, for example, discloses a structure in which at a lower-face side of a floor tunnel 2 are provided a front-side tunnel brace 17 (tunnel reinforcement) which is joined to the floor tunnel 2 substantially at the same position, in a vehicle longitudinal direction, as a first cross member 4 located on a vehicle forward side and a rear-side tunnel brace 18 (tunnel reinforcement) which is joined to the floor tunnel 2 substantially at the same position, in the vehicle longitudinal direction, as a first cross member 15 located in back of the first cross member 4.
In the structure disclosed in the above-described patent document, the first cross member 4 and the front-side tunnel brace 17 are connected by a first front-side seat-attaching bracket 11 which supports a seat where a passenger is seated, and the second cross member 15 and the rear-side tunnel brace 18 are connected by a first rear-side seat-attaching bracket 13.
Thus, by connecting the cross member and the tunnel reinforcement as well as providing the tunnel reinforcement at the floor tunnel, the rigidity of a load transmission path where the side-collision load is transmitted can be more improved, so that the side-collision which is applied to one side, in the vehicle width direction, of the vehicle can be securely transmitted and dispersed to the other side of the vehicle.
Meanwhile, the higher collision safety against the collision where the obstacle collides with the vehicle side has been recently required in order to securely protect a passenger in a cabin. Therefore, there occurs new needs for further improving the mechanical strength of the floor tunnel and the rigidity of the seat-attaching bracket which are both located on the load transmission path where the side-collision load applied to the one side, in the vehicle width direction, of the vehicle is transmitted.